Sound absorbing and deadening material



A. H. BIERT UEMPFEL .Sep t. 12, 1933.

SO UND ABSORBING AND DEADENING MATERIAL Filed March 14, 1931 Patented Sept. 12, 1933 PATENT OFFICE SOUND ABSORBING AND DEADENING MA- TERIAL Albert H. Biertuempfel, Newark, N. J.

Application March 14,

3 Claims.

This invention relates, generally, to sound absorbing and deadening material; and the invention'has reference, more particularly, to a novel material adapted for either surfacing the walls,

6 ceilings, floors or other exposed areas of auditoriums, theaters, rooms or other chambers, and for enclosing steel and iron work to insulate the same from the effects of heat, or for producing full partition walls and the like with or without internal reenforcement, and to the process of producing the same.

This invention has for its principal object to provide a novel sound absorbing and deadening material for use in building construction and a process for producing the same, the said material being adapted to be produced cheaply in any desired form, such as sheet or panel form, and which may be conveniently and economically applied in buildings to form the interior surfaces of auditoriums, theaters, rooms or other chambers, or full dividing partitions for the same, the said material acting to both absorb and break up sound waves so that the same are not reflected from the interior room surfaces, thereby eliminating confusing reverberation of sound in such places and greatly improving the acoustics thereof, and also serving as heat and fire resistant material.

Another object of the present invention lies in 0 the provision of a novel sound absorbing and deadening material, which by virtue of its sound deadening qualities serves to thoroughly sound insulate one room or chamber from another, so that noises produced in one room or chamber are checked and absorbed and are thereby prevented from disturbing occupants of adjoining chambers.

A third object of the present invention is to provide a novel sound absorbing and deadening material which is substantially fire and waterproof, the said material having high heat insulating qualities, whereby the same serves as a valuable heat insulating medium for buildings in addition to performing its function of sound absorbing and deadening.

Still another object of the present invention is to provide a novel construction of sound absorbing and deadening material which is strong, durable and vermin proof, the same being formed easily and economically in a plurality of integrally bound and dissimilar layers consisting largely of waste by-products, the said material being adapted to have its exposed finished surface provided with any desired finish to suit the requirements of any particular insulation, such as,

1931. Serial No. 522,595

for; example, a velvet, corrugated, waved, or screened exposed surface with small perforations or indentations therein.

Briefly stated, in the preferred form of the invention the same is built up in two layers or panels which are integrally joined to one another and form a rigid building material. Both of the two layers are of such character as to act to materially lessen the transmission and reflection of sound. The inner or bottom layer consists of a mass of porous or interstitial material providing relatively large air spaces or interlocking air cells running in various directions. This material preferably consists of waste or byproduct cork material which has been treated with a fire and waterproof binder to render the same substantially fireproof and waterproof.

The outer or finished layer consists preferably of granulated cork which is cemented or held together by a suitable fireproof and waterproof binder. This finished layer may have any desired face finish and preferably has small perforations therein through which sound waves are adapted to pass to be trapped and dissipated in the relatively large interlocking air cells of the inner or bottom layer.

The preferred method of producing the novel sound absorbing and deadening material of this invention consists in treating or impregnating curled cork shavings with a fireproofing and waterproofing binder and before the binder has set, the treated shavings are spread out in a layer in a mold or form. A coarse cloth of relatively open mesh is also treated with the binder and is then spread out over the top of the inner layer. The top layer is next applied and consists of an intimate mixture of granulated cork or other vegetable material together with the fireproof and waterproof binder in somewhat liquid form. The surplus liquid binder of this top layer screens through the coarse cloth and passing over the shavings of the inner layer collect at the bottom of the mold and upon hardening form a rigid back wall for the material. The exposed surface of the top layer may be finished in any manner desired such as rough or smooth or provided with perforations leading into the interstices of the inner layer.

Before the material has set, a pressing operation may be performed on the two layer construction, if desired, so as to assure the rigid adhesion of the inner and outer layers. If this operation is performed, however, the pressure exerted should not be so great as to unduly compact the cork shavings of the inner layer for to do so would relating qualities of this layer.

'Other objects of this invention, not at this time more particularly enumerated, will be clearly understood from the following detailed description of the same.

The invention is clearly illustrated in the accompanying drawing, in Which:

Fig. l is a perspective view of a slab or sheet of the novel sound absorbing and deadening material made according to and embodying the principles of this invention.

Fig. 2 is an enlarged sectional view of a fragmentary portion of the structure shown in Fig. 1; and

Fig. 8 is a perspective view with parts broken away illustrating the steps and the process of manufacturing the novel sound absorbing and deadening material of this invention.

Similar characters of reference are employed in all of the above described views to indicate corresponding parts.

Referring now to said drawing, the reference numeral 1 designates the novel sound absorbing and deadening material of this invention as a whole. This material comprises an inner layer 2 made up preferably of cork shavings 3 which are bound together by a fireproof and waterproof binder 4 into a substantially rigid mass. The binder 4. is adapted to be applied to the shavings 3 while this binder is in liquid form, and upon hardening or setting the same unites the various shavings into a solid and unitary porous or interstitial mass, wherein the interstices or voids are relatively large and interlock with one another throughout the mass of the layer 2. The binder 4 forms a continuous back or sheet 5 at the rear of inner layer 2. The material 1 is provided with an outer or finished layer 7, which is preferably made up of granulated cork 8, although other vegetable substances may be used, such as wood particles, for example, balsa wood particles or fibres.

The cork granules 8 are thoroughly intermixed and bound together bythe fireproofing and waterproofing binder 4. A coarse cloth 10, such as cheesecloth, is interposed between the inner and outer layers of the material 1. The specimen of the material 1 shown in the drawing, is illustrated as having its outer layer '7 provided with a somewhat roughened finished surface, which surface is formed with a plurality of spaced apertures 11 which extend through the outer layer 7 and through the cloth 10 into the inner layer 2 of the material..

The raw materials used in forming the novel building material of this invention preferably consists of wasteproducts which may be obtained very economically, resulting in the production of a cheap article. Thus, the basic raw material used in forming the layer 2 consists preferably of cork shavings such as the curled cork shavings formed as a waste product in the manufacture of corks. The basic raw material used in fabricating the finished or outer layer '7 consists preferably of cork granules which are also obtained as a Waste product and which are preferably screened so as to be of substantially uniform size. In some instances other vegetable granulates or fibers may be used, for example, balsa wood fibers.

The preferred method of fabricating the novel material 1 consists in initially mixing the cork shavings 3 with a suitable fireproofing and Waterproofing binder 4. Various binders may be used, such as cement plaster or plaster of Paris,

duce the size of the air voids and impair the insubut preferably a mixture of magnesite and dilute magnesium chloride solution (18% magnesium chloride and 82% water) is used. This binder in liquid or semisolid form may be put in a mechanical mixer of. the agitator type together with the cork shavings, wherein these shavings are thoroughly intermixed with the binder and are thereby coated with a thin layer of the fireproofing and waterproofing binder. Before the bindor has set or hardened on the shavings, they are removed from the mixer and distributed in a layer in the bottom of a mold or form 9 (see Fig. 3), which layer is to form the inner layer 2 of the material of this, invention.

A coarse cloth 10, such as cheesecloth or burlap is then spread over the treated shavings 3. The coarse cloth 10 is preferably also treated with the liquid fireproofing and waterproofing binder before this cloth is placed upon the treated shavings 3 and is spread over the shavings before the binder has set. After the cloth 10 has been applied over the inner layer, the material forming the outer layer 7 is applied. This material consists of an intimate mixture of preferably screened, granulated cork 8 and the waterproofing and fireproofing binder 4, which binder is preferably in a somewhat more liquid form than that used in treating shavings 3. Some of this liquid binder passes through the cloth l0 and trickling over the shavings 8 collects in the 1 bottom of the mold 9 to subsequently form the solid back or sheet 5. The quantity of binder which trickles through the cloth 10 and over the shavings 3 may be controlled at will by varying the viscosity of the binder, and consequentlythe thickness of the back or sheet 5 may be thusly controlled. The back or sheet 5 provides a solid, continuous rear surface for the inner layer 2 when the binder has hardened, which back or sheet '5 is thoroughly and rigidly bound to the shavings 3.

The top layer 7 may be finished in any manner desired. Thus, this surface may be smooth, rough or corrugated or may be embossed with colors, figures or various decorations, or the same may be given an engraved appearance as by the use of an upper mold half having suitable indicia. If desired, before the binder has set, a slight pressing operation may be performed on the two layer construction thus provided, as by pressing the upper mold half down upon the top of layer 7. This pressing operation will even more firmly bind the inner and outer layers together.

In the sample shown in the drawing, the outer layer '7 is illustrated as having a somewhat roughened finished surface which is perforated at intervals by small apertures 11 which extend through this layer and through the cloth 10 into the inner layer 2. 11, a certain portion of the sound waves striking the material passes through these apertures andenters the voids of the inner layer 2 where By employing the apertures these sound waves are broken up and lose their to the wall studding or to the wall surfaces of a I room to be provided therewith. The panels or serves to readily absorb sound waves and prevents the refiection of the same, thereby elimi nating annoying and confusing reverberation or echoing of sounds transmitted within the room or chamber. Owing to the inherent insulating qualities of the cork and the presence of the voids in the inner layer 2, the novel material of this invention is particularly valuable in insulating rooms in buildings against heat and cold, so that the same serves this valuable function in addition to its sound absorbing and deadening functions.

It will be apparent that the novel material of this invention may be made in varying thicknesses, from thin panels to be applied to wall areas to thick partitions for dividing one room from another. The finished layer '7 may be made very thin, if desired, and in some instances may consist simply of a layer of the binder 4 so that both sides of the material will have the same external appearance.

It isobvious that the cloth 10 may be made of soft metal, if desired, such as copper screening and a layer of this cloth may be placed in the mold 9 before the shavings 3 are placed there in, in which case both sides of the inner layer 2 would be provided with the cloth binding 10 which also serves to strengthen the material. In some instances it will be desirable to include metal or other reenforcement within the body of the shavings 3 to thereby even further strengthen this material, especially when the same is to be used for partitions.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A rigid composite slab comprising, an inner layer consisting of a multiplicity of intermixed curled cork shavings having hollow interiors, said cork shavings being treated with a waterproof and fireproof hardened plastic cement, said curled shavings being united by said hardened plastic cement to form said inner layer having a plurality of relatively large air chambers therein due to the hollow nature of said curled shavings and to the voids existing between adjacent shavings, said hardened plastic cement forming a substantially continuous and relatively thin sheet adhering to one side of said layer, a cloth impregnated with said hardened plastic cement and adhered to the other side of said layer, and an outer layer adhered to said inner layer through said impregnated cloth, said outer layer consisting of granules of cork held together by said hardened plastic cement.

2. A rigid composite slab comprising, an inner layer consisting of an intermixed mass of curled cork shavings providing concavities therewithin, a waterproof and fireproof hardened plastic cement coating said curled shavings and retaining the same in a unitary solid mass having interlocking voids extending in all directions therethrough, an outer layer consisting of a mixture of relatively small solid vegetable particles and additional waterproof and fireproof hardened plastic cement serving to bind said vegetable particles together, and a coarse cloth interposed between said inner and outer layers, said coarse cloth being united to said layers by said hardened plastic cement.

3. A rigid composite slab comprising, inner and outer layers, said inner layer consisting of a mass of hollow curled cork shavings providing a multiplicity of substantial air chambers distributed throughout said layer, a waterproof and fireproof binder coating said shavings and uniting the same into a unitary solid layer, the outer layer comprising small cork granules and a waterproof and fireproof binder closely uniting said granules to form a solid whole, and a cloth interposed between said layers and united thereto by said binders, said outer layer and said cloth having a multiplicity of aligned apertures therein, whereby sound waves striking the outer surface of said outer layer may pass inwardly into the relatively large chambers provided within said inner layer to become deadened therewithin.

ALBERT H. BIERTUEMPFEL. 

